Mesoporous Amorphous Bulk Material Electrodes for Ultrahigh Volumetric Capacity Electrochemical Capacitors.

Retaining satisfactory electrochemical performances under high-mass electrode-active-matter loadings is important for energy storage. However, the performance decreases with increasing mass loadings due to a reduction in the ion/electron transport. In this study, a novel mesoporous amorphous bulk (MAB) material strategy is proposed.

Clinical application of BIS combined with LCR in assessing brain function and prognosis of patients with severe carbon monoxide poisoning.

Background: This study investigated the value of the bispectral index (BIS) and lactate clearance rate (LCR) in the assessment of cerebral neurological injury and prognosis in acute severe carbon monoxide poisoning (ASCOP) patients.

Methods: A retrospective study was conducted on 86 ASCOP patients admitted to our hospital from November 2019 to March 2021. The patients' prognosis neurological function of the brain after 3 months of treatment was observed.

Self-assembly of Au nanocrystals into large-area 3-D ordered flexible superlattice nanostructures arrays for ultrasensitive trace multi-hazard detection.

Plasmonic nanoparticles that self-assemble into highly ordered superlattice nanostructures hold substantial promise for facilitating ultra-trace surface-enhanced Raman scattering (SERS) detection. Herein, we propose a boiling-point evaporation method to synthesize ordered monocrystal-like superlattice Au nanostructures (OML-Au NTs) with a polyhedral morphology. Combined with thermal nanoimprint technology, OML-Au NTs were directly transferred to impact-resistant polystyrene (IPS) flexible SERS substrates, the obtained flexible substrates (donated as OML-Au NTs/IPS) detection limit for R6G molecules as low as 10 M.

In Situ Structural Dynamics of Atomic Defects in Tungsten Oxide.

Atomic defects are critical to tuning the physical and chemical properties of functional materials such as catalysts, semiconductors, and 2D materials. However, direct structural characterization of atomic defects, especially their formation and annihilation under practical conditions, is challenging yet crucial to understanding the underlying mechanisms driving defect dynamics, which remain mostly elusive. Here, through atomic imaging by an aberration-corrected environmental transmission electron microscope (AC-ETEM), we directly visualize the formation and annihilation mechanism of planar defects in monoclinic WO on the atomic scale in real time.

Revealing synergetic structural activation of a CuAu surface during water-gas shift reaction.

Bimetallic alloy catalysts show strong structural and compositional dependence on their activity, selectivity, and stability. Often referred to as the “synergetic effect” of two metal elements in the alloys, their detailed dynamic information, structurally and chemically, of catalyst surface under reaction conditions remains largely elusive. Here, using aberration-corrected environmental transmission electron microscopy, we visualize the atomic-scale synergetic surface activation of CuAu under a water–gas shift reaction condition.

Structural Evolution of Cu/ZnO Catalysts during Water-Gas Shift Reaction: An Transmission Electron Microscopy Study.

Supported metal catalysts experience significant structural evolution during the activation process and reaction conditions, which is critical to achieve a desired active surface and interface enabling efficient catalytic processes. However, such dynamic structural information and related mechanistic understandings remain largely elusive owing to the limitation of real-time capturing dynamic information under reaction conditions. Here, using environment transmission electron microscopy, we demonstrate the atomic-scale structural evolution of the model Cu/ZnO catalyst under relevant water-gas shift reaction (WGSR) conditions.

Atomic-Scale Interfacial Phase Transformation Governed Cu Oxidation in Water Vapor.

Metal oxidation initiates from surface adsorption to subsurface and bulk reaction through continuous interfacial phase transformation from metals to oxides. How the initial interfacial process affects the whole process of metal oxidation remains largely elusive because of the lack of direct observation of the evolving interface. Here, through atomic-scale environmental TEM observations of Cu surface reaction in water vapor, we demonstrate that the interfacial strain between the substrate and growing oxide is coupled into the continuing chemical reaction that determines the reaction kinetics.

Atomic Scale Mechanisms of Multimode Oxide Growth on Nickel-Chromium Alloy: Direct Observation of the Initial Oxide Nucleation and Growth.

The initial growth mode of oxide on alloy plays a decisive role in the development of protective oxide scales on metals and alloys, which is critical for their functionality for high temperature applications. However, the atomistic mechanisms dictating that the oxide growth remain elusive due to the lack of direct observation of the initial oxide nucleation and growth at atomic-scale. Herein, we employed environmental transmission electron microscopy and the first-principles calculations to elucidate the initial atomic process of nickel-chromium (Ni-Cr) alloy oxidation.

Direct Visualization of Atomic-Scale Graphene Growth on Cu through Environmental Transmission Electron Microscopy.

The functionalities of two-dimensional (2D) materials are solely determined by their perfect single-layer lattice or precisely stacking of multiple lattice planes, which is predominately determined during their growth process. Although the growth of graphene has been successfully achieved on different substrates with a large area up to millimeters, direct visualization of atomic-scale graphene growth in real time still lacks, which is vital to decipher atomistic mechanisms of graphene growth. Here, we employ aberration-corrected environmental transmission electron microscopy (AC-ETEM) to visualize the nucleation and growth of graphene at the atomic scale in real time.

Atomic-Scale Dynamic Interaction of H_{2}O Molecules with Cu Surface.

Atomic-scale interaction of water vapor with metal surfaces beyond surface adsorption under technologically relevant conditions remains mostly unexplored. Using aberration-corrected environmental transmission electron microscopy, we reveal the dynamic surface activation of Cu by H_{2}O at elevated temperature and pressure. We find a structural transition from flat to corrugated surface for the Cu(011) under low water-vapor pressure.

Real-Time Atomic-Scale Visualization of Reversible Copper Surface Activation during the CO Oxidation Reaction.

By using in situ aberration-corrected environmental transmission electron microscopy, for the first time at atomic level, the dynamic evolution of the Cu surface is captured during CO oxidation. Under reaction conditions, the Cu surface is activated, typically involving 2-3 atomic layers with the formation of a reversible metastable phase that only exists during catalytic reactions. The distinctive role of CO and O in the surface activation is revealed, which features CO exposure to lead to surface roughening and consequently formation of low-coordinated Cu atoms, while O exposure induces a quasi-crystalline CuOx phase.

Highly Efficient Multifunctional Co-N-C Electrocatalysts with Synergistic Effects of Co-N Moieties and Co Metallic Nanoparticles Encapsulated in a N-Doped Carbon Matrix for Water-Splitting and Oxygen Redox Reactions.

Electrochemical water-splitting reactions (hydrogen evolution reaction (HER) and oxygen evolution reaction (OER)) and oxygen redox reactions (oxygen reduction reaction (ORR) and OER) are core processes for electrochemical water-splitting devices, rechargeable metal-air batteries, and regenerative fuel cells. Developing highly efficient non-noble multifunctional catalysts in the same electrolyte is an open challenge. Herein, efficient Co-N-C electrocatalysts with a mixed structure comprising Co-N moieties and Co nanoparticles encapsulated in a N-doped carbon layer were prepared via pyrolysis of a new structure of Co-coordinated bis(imino)pyridine polymer constructed by 2,6-diacetylpyridine and 3,3'-diaminobenzidine.

Enhanced Visible Light Photocatalytic Performance of G-C3N4 Photocatalysts Co-Doped with Gold and Sulfur for Degradation of Persistent Pollutant (Rhodamine B).

In order to overcome the intrinsic drawback of pristine g-C₃N₄, a nano-composite photo-catalyst Au/S-C₃N₄ with controllable nanoscale gold (Au) particles was successfully synthesized by a facile liquid chemical preparation process. It was found that the content of chloroauric acid (AuCl₃ · HCl · 4H₂O) play crucial role in both the diameter and the density of the Au nanoparticles. The results showed that as-prepared Au/S-C₃N₄ nanosheets with 2 wt% Au loaded content exhibited excellent photocatalytic decomposition of RhB under visible light irradiation as compared with other Au loadings (i.

Ferroelectric Polarization-Modulated Interfacial Fine Structures Involving Two-Dimensional Electron Gases in Pb(Zr,Ti)O/LaAlO/SrTiO Heterostructures.

Interfacial fine structures of bare LaAlO/SrTiO (LAO/STO) heterostructures are compared with those of LAO/STO heterostructures capped with upward-polarized Pb(Zr,Ti)O (PZT) or downward-polarized Pb(Zr,Ti)O (PZT) overlayers by aberration-corrected scanning transmission electron microscopy experiments. By combining the acquired electron energy-loss spectroscopy mapping, we are able to directly observe electron transfer from Ti to Ti and ionic displacements at the interface of bare LAO/STO and PZT/LAO/STO heterostructure unit cell by unit cell. No evidence of Ti is observed at the interface of the PZT/LAO/STO samples.

Polypyrrole Whelk-Like Arrays toward Robust Controlling Manipulation of Organic Droplets Underwater.

Whelk-like polypyrrole (PPy) arrays film is successfully prepared by electropolymerization of pyrrole in the presence of low-surface-energy tetraethylammonium perfluorooctanesulfonate (TEAPFOS) as dopant. The underwater wettability of PPy whelk-like arrays can be successfully tuned by electrical doping/dedoping of PFOS ions. Interestingly, CCl droplets with microliter-size as a representative sample are gathered together to form a larger droplet underwater at the potential of +0.

Intrinsic ferromagnetism and quantum transport transition in individual Fe-doped BiSe topological insulator nanowires.

Time-reversal symmetry is broken by magnetic doping in topological insulators (TIs). An energy gap at the Dirac point opens and thus, generates numerous surface carriers. TI nanostructures are an ideal platform to investigate exotic surface transport behavior due to their large surface-to-volume ratio, which enhances the contribution of the TI surface states.

Electroplating lithium transition metal oxides.

Materials synthesis often provides opportunities for innovation. We demonstrate a general low-temperature (260°C) molten salt electrodeposition approach to directly electroplate the important lithium-ion (Li-ion) battery cathode materials LiCoO, LiMnO, and Al-doped LiCoO. The crystallinities and electrochemical capacities of the electroplated oxides are comparable to those of the powders synthesized at much higher temperatures (700° to 1000°C).

Ternary PtRhFe Nanoscale Alloys as Highly Efficient Catalysts with Enhanced Activity and Excellent CO-Poisoning Tolerance for Ethanol Oxidation.

To address the problems of high cost and poor stability of anode catalysts in direct ethanol fuel cells (DEFCs), ternary nanoparticles PtRhFe (x = 1, 3, 5, 7, and 9) supported on carbon powders (XC-72R) have been synthesized via a facile method involving reduction by sodium borohydride followed by thermal annealing in N at ambient pressure. The catalysts are physically characterized by X-ray diffraction, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy, and their catalytic performance for the ethanol oxidation reaction (EOR) is evaluated by cyclic and linear scan voltammetry, CO-stripping voltammograms, and chronopotentiometry. All the PtRhFe/C catalysts of different atomic ratios produce high EOR catalytic activity.

The Effect of Boron Doping on Structure and Electrochemical Performance of Lithium-Rich Layered Oxide Materials.

Polyanion doping shows great potential to improve electrochemical performance of Li-rich layered oxide (LLO) materials. Here, by optimizing the doping content and annealing temperature, we obtained boron-doped LLO materials Li1.2Mn0.

Magnetoelectricity coupled exchange bias in BaMnF4.

Multiferroic BaMnF4 powder was prepared by hydrothermal method. Hysteretic field dependent magnetization curve at 5 K confirms the weak ferromagnetism aroused from the canted antiferromagnetic spins by magnetoelectric coupling. The blocking temperature of 65 K for exchange bias coincides well with the peak at 65 K in the zero-field cooled temperature-dependent magnetization curve, which has been assigned to the onset temperature of two-dimensional antiferromagnetism.

Solvothermal Synthesis of Lateral Heterojunction Sb2Te3/Bi2Te3 Nanoplates.

A lateral heterojunction of topological insulator Sb2Te3/Bi2Te3 was successfully synthesized using a two-step solvothermal method. The two crystalline components were separated well by a sharp lattice-matched interface when the optimized procedure was used. Inspecting the heterojunction using high-resolution transmission electron microscopy showed that epitaxial growth occurred along the horizontal plane.

Insights into the growth of bismuth nanoparticles on 2D structured BiOCl photocatalysts: an in situ TEM investigation.

The synthetic techniques for novel photocatalytic crystals had evolved by a trial-and-error process that spanned more than two decades, and an insight into the photocatalytic crystal growth process is a challenging area and prerequisite for achieving an excellent photoactivity. Bismuth nanoparticle based hybrids, such as Bi/BiOCl composites, have recently been investigated as highly efficient photocatalytic systems because of the localized surface plasmon resonance (LSPR) of nanostructured bismuth. In this work, the observation towards the formation and growth of bismuth nanoparticles onto 2D structured BiOCl photocatalysts has been performed using a transmission electron microscope (TEM) directly in real time.

Electrocatalytic Hydrogen Evolution Reaction on Edges of a Few Layer Molybdenum Disulfide Nanodots.

The design and development of inexpensive highly efficient electrocatalysts for hydrogen production underpins several emerging clean-energy technologies. In this work, for the first time, molybdenum disulfide (MoS2) nanodots have been synthesized by ionic liquid assisted grinding exfoliation of bulk platelets and isolated by sequential centrifugation. The nanodots have a thickness of up to 7 layers (∼4 nm) and an average lateral size smaller than 20 nm.

Stable underwater superoleophobic and low adhesive polypyrrole nanowire mesh in highly corrosive environments.

Underwater superoleophobic materials with low adhesion have been widely researched owing to their self-cleaning and anti-corrosive properties. In this study, polypyrrole (PPy) nanowire meshes have been successfully fabricated by in situ electrochemical polymerization on stainless steel mesh substrates in the presence of phosphate buffered saline as both an electrolyte and a dopant. PPy nanowire meshes have high oil contact angles (above 150°) and low sliding angles (less than 10°), and they show underwater superoleophobicity with an excellent self-cleaning performance, not only in pure water, but also in highly corrosive aqueous solutions, including salt solutions, strong acids or basic solutions.

Magnetic interactions in BiFe₀.₅Mn₀.₅O₃ films and BiFeO₃/BiMnO₃ superlattices.

The clear understanding of exchange interactions between magnetic ions in substituted BiFeO3 is the prerequisite for the comprehensive studies on magnetic properties. BiFe0.5Mn0.